Side coupled carriers that pass to opposite sides of obstructions



v. M. JOHNSON 2,673,366 sIDE couPLEn CARRIERS THAT PAss To OPPOSITE sIDEs oF oEsTRucTIoNs 2 Sheets-Sheet 1 March 30, 1954 Filed April 26, 1951 March 30, 1954 NsoN 2,673,366

v. M. JoJ-l SIDE COUPLED CARRIERS THAT PASS TO OPPOSITE SIDES OF OBSTRUCTIONS Filed April 26, 1951 2 Sheets-Sheet 2 VernonIZJ'OhnSon/ INvgNoR ATTORNEY atentecl Mar. 30, 1.954f

UNITED ds TArEs PATENT SIDE .COUPLED CARRIERS 'ILHAT PASS .TO OPPOSITE 'SIDES 0F .DESTRUCTION S '8 Claims.' :1 .'The present invention relates `to carriers oi. .appliances 'that clean, sand, and ,perform vother operations to surfaces.

An object of 'the 'invention is 'to provide a car- Iier of this character capable of supporting and moving appliances Afor simultaneously 'eiecting operations to door ,surfaces on opposite sides of upstanding members attached to a floor, such .as .desk- .and chair-.supports in .schoolrooms Another object of .the invention is to provide .a carrier .having a main unit and an auxiliary unit -connected side .by y.side and movable'together .over a floor surface, .said connection between said units .being .such that the .units may be `passed .by and on .opposite .sides of members .attached to a oor.

A ,further .object .of the invention is to provide .a carrier -as set forth above which supports a floor-surfacing .appliance on each of .a .pair of carrier units connected to .each other'by a .number .of couplings .constructed and arranged in a manner that when .movingone carrier .unit .ina single 7general direction across .a floor having upstanding members .attached thereto, the other carrier unit .is moved therewith and may pass to Yan opposite side of the upstanding members .and `under structures supported by .said ups'tanding members while both .units vremain connected together, 'the .couplings .being progressively .and automatically disconnected and reconnected one at a time .by .engagement with the upstanding members during the .passing of .said .upstanding members through said couplings.

A still further object .of the invention is the provision of a carrier as outlined .in .the above objects wherein the couplings .between .different units of the carrier comprise both draft and `electrical connections for continually supplying electric current to an appliance on .the auxiliary carrierunit as said auxiliarycarrier unit is moved over the :door surface by movement of .the main carrier unit.

It is also van object of the invention to provide a novel and improved appliance carrier in accordance with the preceding objects which is substantial in construction, economical to manufacture, and thoroughly eHicient and practical in vuse.

These, together with various auxiliary features and objects of the invention which will later become apparent .as the following description proceeds, are attained by the present invention, a preferred lembodiment of which has been illustrated, by way =of example only, inthe accompanying drawings, wherein:

Figure 1 iis a .side `elevation `of Vthe carrier lshowing electrically Qperated 'tank-type vacuum clean- `ers .arranged "thereon:

Figure v2 is va .plan view of same;

.Figure B `is .a fragmentary -plan and .sectional view showing one coupling 'in connected posi- 'tion and another coupling in disconnected positiong.

"Figure .4 is an enlarged sectional view 'through a coupling in connected position;

Figure T5 is .a fragmentary face ,View looking in the direction indicated vby 'the ,dotfand-.dash ,line and arrows .5-5 inFigure'S;

Figure 6 is a V,cross vsection taken on line l-.6 .of .Figure v4: y

Figure 7 Vis a .fragmentary section online ",'l-l of Figure ,3; `and Figure 8 .is a .fragmentary vertical section on line 8--8 ,of Figure .3.

Referring now more `specifically to the accompanying drawings, wherein .like numerals designate similar parts throughout :the various views, attention is directed rst to 'Figures 1 and .2 wherein it will 'be seen that a main unit and an .auxiliary .unit of the carrier indicated by the numerals v'l0 and AI 1 respectively, .are shown coupled .togetherand arranged side bygside and each as supporting one of .a `pair .of electrically `operated tank-type vacuum cleaners I2 ,and .|3. The cleaner l2 on .themain .unit l0 is .supporteddi- `ferently and ,is of slightly different .construction from thatl of the cleaner .L3 .supported .on the auxiliary unit |.I yfor reasons which will beset forth as the description proceeds.

Each of -the units l0 .and ITI .of .the carrier is constructed as having a rectangular frame I4 with a :pair of plain wheels or rollers .[5 rotatably vsupported .at the rear -end thereof and a vpair of caster-.type wheels or rollers .Hi mounted -at the forward .end for lfree, 4guided movement of the `carrier over the @licor surface. The .adjacent side members .I1 -of fthetwo frames M -are .spaced by .couplings a .suflicient .distance apart to permit .the y.passing thereof to v.Qlposite sides .of .up- .standing members, indicated by thefnumeral I8 and shown as zdesk.. .and .chair-supports lby .dash- `and-.dot lines in Figures `.1 land 2, while ,rolling the carrier over .the hoor surface. "llo vassist .in directing the .frames 15.4 to QpDosite lsides .of the supportsll, the forward .ends Aof the kside members .I1 of said f-ramesgproject forwardly, .as .at 1.19, .and are curved .away Iromone anothenasclearly shown in Figures 2 and .3.

.To theside member 'IJ and opposite .side ,mem-

'ber "20 of each 'frame 'Il are secured brackets 2l with openings 22 therein which pivotally receive trunnions 23 secured to the body of the appliance, which in the present case is a tank of a vacuum cleaner. The brackets 2l on the side members of the frame or the main carrier unit lil extend upwardly and support the tank l2a of the vacuum cleaner i2 on an elevation above the trarne i4, while the brackets 2l of the frame of the auxiliary carrier unit H are directed downwardly for supporting the tank I3a of the vacuum cleaner i3 at a lower elevation between the side members il and 2li. Besides the tanks of the cleaners be ing at different elevations, the cleaner l2 is arranged slightly in advance or the cleaner i3. Oirset to the forward side of one trunnion 23 of each cleaner and movable therewith on the pivotal connections of the trunnions is an arm 24 through which extends a headed rodV 25 that also extends through a bracket 2t fixed to the frame side member 2@ and has threaded thereon a thumb nut lil for adjustably raising and lowering the headed end or the rod 25. Between the brackets it and arms 24 and around the rods 25 are coil springs 28 yieldably urging the arms downwardly and against the heads on the rods. Thus, it can be seen that the cleaners I2 and i3 may be independently swung on the pivotal ccnnections of their trunnions in one direction against tension of the springs 2li, but are held by the adjusted position o the heads on the rods against movement in the opposite direction.

On the forward side of the tanks We and is of the cleaners l2 and i3 are rigidly attached right-angled air conduits 29 that extend forwardly and then downwardly, and to the downs" .ward ends are adjustably mounted for horizontal turning movement heads Sill that open onto the floor surface. The heads are elongated, and be ing adjustable, permit the positioning thereor at angles for overlapping of the floor surface cov Y ered by the two heads, resilient end pieces 3l on the heads being provided which are iiexed rearwardly upon engagement thereof with the supports i8 attached to the door. A conduit extension 32 between the conduit 29 and head ci the cleaner l2 cares for the greater elevation of the tank l2a over that of the tank tifi; otherwise, except for the fact that the cleaners l2 and i3 are rights and lets, the construction of both is substantially the same.

To the inside of the side member li ci the trarne of the main carrier unit l at spaced locations throughout its length are secured by welding or the like one end of each of a plurality of horizonn tally arranged cylinders 'd3 that lie parallel to one another and project towards the opposite side member of said frame. Centrally of the cylinders 33, the side member Il is provided with circular openings 34 through which the orward ends of sleeves slidably mounted in the cylinders 33 are moved to positions projecting through the openings 34. The openings 34 and cylindrical portions 35a or the sleeves 35 which slide through the openings are of less diameter than the inside diameter of the cylinders 3&3 producing annular shoulders 3&5 at the attached ends ci the cylinders 33 against which annular flanges 37 on the sleeves 35 abut when said sleeves are at rest in their normal coupled positions with their ends projecting through the openings 34. The cylindrical portions 359d of the sleeves 35, being arranged in the cylinders 33 and spaced from the walls thereof, are supported at their forward ends and guided during their sliding movement by balls 38 held in recesses in the flanges 31 and engaging the inner surfaces of the walls of the cylinders 35, and are supported and guided at their rear ends by balls 39 engaging their outer wall surfaces and located in recesses in ring-shaped closure members 4Q threaded into the unattached ends of the cylinders 33. Coil springs 4I located between the walls of the cylinders 33 and slidable sleeves 35 bear at their opposite ends against the flanges 3l and ring-shaped closure members 4t ior yieldably forcing the sleeves to positions with the iianges 31 in engagement with the shoulders 35.

Within the slidable sleeves 35 and also arranged fcr endwise sliding movement are tubular members 42 which are supported and guided in their sliding movement similar to that of the sleeves by the use of ball-supporting anges and ball-supporting ringushaped closure members 43 and 44, respectively. The tubular members likewise are yieldably forced in the same direction as that of the slidable sleeves 35 by coil springs 45; but instead of the springs 45 bearing at one end again the flanges 43, they apply pressure to the bottoms of cup-shaped members 46 slidable on the wall of the cylindrical portion 35e and adjustably attached to the tubular members, as at 41, whereby said cup-shaped members serve the purpose of limiting sliding movement of the tubular members in the slidable sleeves against tension or the springs 45.

As shown in Figure 7, keys 48 are provided on the flanges 3l of the sleeves 35 and are slidably received in slots 45 in the walls of the cylinders 33 for preventing turning movement of said sleeves. Similar keys 5B are also provided on the flanges of the tubular members 42 and are received in slots 5l in the cylindrical portions 35a of the sleeves 35 for preventing turning movement or these parts with respect to one another.

The forward ends or the sleeves 35 are coneshaped, as at 52, gradually decreasing in diameter as they extend forward and are ci less diameter at their larger end portions than the cylindrical portions 35a, thereby providing annular shoulders 53 at the ends of the said cylindrical portions. These shoulders are adapted to abut the outer side of the side member l1 of the frame of the auxiliary carrier unit Il at locations around tapered circular openings 54 in said side member il through which the cone-shaped portions 52 project. The openings 54 are spaced the same distances apart as that of the spacing of the cylinders 33 attached to the member i' of the main carrier unit; and the abutting of the shoulders 53 against the side member Il of the auxiliary carrier unit spaces the side member l1 of both carrier units parallel to one another and the proper distance apart.

Attached by welding or the like on the inside oi the side member I'l of the auxiliary carrier unit ll are arched reinforcing and supporting bars 55 bridging the openings 54 inl said side member. Supported on the arched bars 55 in alignment with the openings 54 are electric plugs 55 having the electricity-conducting prongs 51 thereof directed towards the opening 54 for en* gagement with spring contacts 53 oi electric re ceptacles 59 housed in the forward ends of the tubular members 42.

Mounted in the forward end of the cylindrical portion 535e of each sleeve 35 are c. pair of posi.- tively actuated locking bolts are entendn ed outwardly ci said cylindrical portion and in engagement with angled surfaces iii on the side member l of the main carrier unit lil and at opposite sides of an opening 34 when coupled :fs toitheauxiliary carrier eunit IEI.. .n similar pair :of .locking bolts 62 are apivotally mounted in the forward Iend vof :the .cone-shaped iportion .52 .of each :sleeve 3 5 and -engage like angled .surfaces 63 at opposite sides of the tapered opening y.'54 on vthe inside vof .the .member Is'I tof 4'the auxiliary carrierunit 1I I `when coupled.

The locking bolts 6.0 .and l62 :are pivoted,.as .at 4E4 and 65, respectively, Ainwardlyof'the sleeve '35 and `are swung outwardly .of the outer .surfaceof `the cylindrical portions 35iand-coneshaped portions 52 :through .slots 66 and ,61, respectively, vin the walls of said portions. Other slots 68 rand 169 are provided in the locking .bolts BIJ and .62, respectively, and are arranged rat angles to the di- .rection :of movemerrtof the tubular members e2 :in the sleeves, `and through `said slots YIB ,and 6.9 are extended portions of loops .1.0 and I, :respectively, which fare attached 'to the tubular mem- A.bers .42 by bolts 'I2-.and :.I3prespectively- Thus, it can beseenthat Sliding movement of the-.tubular :members 4-3 lwith respect to the v'sleeves 13.5 ex- -ltends and retracts the locking vbolts 0 land 62. vI't will also `be noted :that the locking'bolts `(lock .the slidable sleeves 35 against movement with `respect to the main lcarrier unit I0, and .thatithe locking bolts 62 lock the auxiliary carrier vunit -I I kagainst movement on-sa-id sleeves.

Spaced inwardly `of ythe side member 2t! 4of the ,frame I4 .of the .main carrier unit i6 and attached to the end members of said frame is a bar 'I4 on which are pivoted, as `at 151, bell .cranks .'16 with 'the y'arms -'I1:of1each connected 'by a cable 'I8 to a bail 'I9 secured 4to `the rearward end of Va tubular member '42, while the other arm 80 of ea h bell crank I6 extends across the space between the side members I1' of both carrier units for swinging said bell cranks on their pivots when said arms 8G thereof are brought into engagement with upstanding structures, as indicated at I8, yduring passing of the carrier units to opposite sides of the `structures I6. rIhe Vfree `ends of the arms `8l] are'turned rearwardly, as yat 8|, determining the start of movement Yand release yof .the `arms 8U by engagement Awith the supports I6 during forward motion of the .carriers and are curved upwardly as -they extend rearwardly, as shown in Figures 1 :and 3,:for movement'thereof to positions above the increased width-ofthe side member II at the attachment of the cylinders 33 thereto when said .arms are swung to their extreme rearward positions to permit A'passimg ofthe structures I 8.

To 4eliminate side pull .on the rearward -ends rof the tubular members 42 kdue Yto curved -direction of movement of the-outer ends ofthe arms 'H of the bell cranks 'I-B. grooved rollers 82 are mounted on the bar I41around which the 4cables :are pulled, the bar being provided with openings 83 through which the cablesextend.

To the rear end 4member of the frame I4 of the main carrier unit I are attached the lower ends of a pair `.of upstanding bars 184 that have a handle bar 85 extending across and vattached 4to their upper ends. `It is -with vthis handle bar that the operator vpushes the .carrier .over the floor surface. A bracket 816 is attached to one upstanding bar 84 and rotatably supports a reel AS'I upon whichalarge quantity of extension cord 88 leading from the source vof current is wound. Connected tothe electric wires on the reel 81 are wires 89 leading t0 an electric switch 38 mounted on an upright bar vl84. From the switch 90 Velectric wires 3l and r92 extend for `supplying Y'current vto the electric motors (not shown) of lthe cleaners tI2 and I3, respectively. Electric wires 93 .connected Ito 4the :cleaner I-3 mounted son the auxiliary carrier unit SIlI are :also :connected '5to 'all ,of the electric `plugs A5.6 in parallel, while the electric wires '92 arranged on 'the main vcarrier unit .i0 and connected to all of the receptacles 55.9 .in parallel will supply current to the .cleaner 1.3 should `but one ofthe .plugs56 @be in contact with a receptacle 59. The wires .'32 deading from 'the :receptacles 519 extend through the tubular '-.members 42 through the bar 'I4 .and are then con- "nected together lin parallel before ftbeing icon- -nected A.to theswitch 19G.

iIn operation, the carrier tis moved over `the 'iloor surface and guided during its .movementby .pressure on the handle 'bar .'35 'attached to the lmain carrier funit "I0, .the caster wheelsf apervmit-,ting turning of the coupled carrier .units to guide and Ito direct the different units vto opposite sides of :structural members attached tothe door which, as previously stated, will be considered as deskand .chair-supports in a schoolroom. The main .carrier unit `Iii to which the handle bar 85 is attached is moved down the aisles `of the schoolroom with the operator 4.walking thereb-ehind, while the auxiliary carrier unit which supports its cleaner at alower elevation is moved under the desks and chair. Upon engagement of each arm of a `bell crank 'I6 with a deskand chair-support, the end 8'I of-saidfarm 'Sil is prevented from moving forward with 4the remainder of the carrier, and the 'bell crank is thereby swung on its pivot 'I5 moving the arm TI in a direction that applied'a `pull on the cable I8 attached to the tubular vmember 42. 'The coil spring 45 forcing the tubular member in a 'forward direction, lbeing of less streng-th than the coil spring 4I holding the sleeve 35 forwardly, yields to the pull on the cable thereby causing an endwise slidging movement of the tubular ymeniber 42 in the sleeve 35.

Such relationship of movement of parts retracts the locking bolts 66 and 't2 from engagement with the angled surfaces 6I and 63. respectively, before the tubular member reaches the limit of its movement in the sleeve which is terminated yby engagement of the cup-shaped member 45 with the ring --closure member 44; whereupon the Acontinuing of pull .on the cable -slides the sleeve 35 rearwardly in the cylinder 33 aga-inst tension of the spring 4I separating the electric receptacle 53 from the electric plug 56 and withdraws the end of the sleeve to va position such as that shown at the lefthand side of Figure 3, which clears the way for the coupling -to pass the support I8. As soon as the support clears the end of the arm 86, the springs 4I and 45 will `return the parts to normal locked positions prior tothe engagement of ythe next arm 80 of another coupling with the support. The spacing apart of the couplings is su-ch that only one coupling is uncoupled at a time, thus providing sufHcient draft connection and complete `electrical connection at vall times of the .main carrier unit .to the auxiliary :carrier .unit for `efficient operation of the apparatus.

Obviously, the carrier may be Eemployed :for .supporting and moving appliances `other than cleaners over oor surfaces :when applying `a rtre'atm ent Ato 'the surfaces.

VIn view ofthe foregoing description taken lin conjunction .with the accon'ipany-ing drawings, it is 'believed 'that a clear vunderstanding vof .the

"construction, oper-ation, and advantages of the this art. A more detailed description is accordingly deemed unnecessary.

It is to be understood, however, that even though there is herein shown and described a preferred embodiment of the invention, various changes may be made without departing from the spirit and full intendment oi the invention.

What is claimed is:

1. A carrier for applances capable of passing to opposite sides of obstructions; comprising a main carrier unit; an auxiliary carrier unit; a number of horizontally spaced couplings connecting and supporting said units spaced relative to one another for movement of both of said units together over a floor surface ea-ch of said couplings consisting of a cylinder xed to one of said units, a sleeve-like plunger slidably mounted in said cylinder, spring means yieldably extending said plunger into the other of said units, locking bolts movable on said plunger and engageable with the unit into which said plunger is extended, a tubular member slidably supported in said .sleeve-like plunger for limited sliding movement relative to said plunger and connected to said locking bolts so as to operate said locking bolts upon sliding movement of said tubular member, and spring means yieldably holding said tubular member in position with said locking bolts in locked position; pivoted arms on said unit having said cylinders hired thereto for movement into positions engageable with and to be moved by said obstructions during passing of said units to opposite sides of said obstrucions; and means connecting each pivoted arm to a tubular member so as to slide said tubular members, disconnect said locking bolts, and retract said sleeve-like plungers upon the engagement of said arms with obstructions; the spring means on the plungers and the spring means on the tubular members providing the source of power to reconnect said couplings and to return their associated arms to their initial positions after passing" of the obstructions.

2. A carrier for appliances capable of passing to opposite sides of obstructions, comprising a main carrier unit, an auxiliary carrier unit, a number of horizontally spaced couplings connecting and supporting said units spaced relative to one another, rollers mounted on at least one of said units for movement of both of said units together over a surface, and separate means connected to each of said horizontally spaced couplings which progressively and automatically disconnect and connect each of said couplings upon passing of said units to opposite sides of the obstructions, each of said separate means having a part thereof engageable with and actuated b/ the obstructions to disconnect its associated coupling and allow said coupling to pass the obstruction, and each of said separate means also having another part thereof that reconnects its associated coupling immediately after its coupling has passed the obstruction.

3. A carrier for appliances capable of passing to opposite sides of obstructions, comprising a main carrier unit, an auxiliary carrier unit, a number of horizontally spaced couplings connecting and supporting said units relative to one another, rollers mounted on at least one oi said units for movement of both of said units together over a surface, arms engageable with and actuated by the obstructions during the passing of said units to opposite sides of the obstructions, each arm being operatively connected to a separate coupling so as to disconnect each coupling during movement thereof past each obstruction, and separate spring means that connect each coupling and return its associated arm to its initial position after the passing of said obstructions.

4. A carrier for appliances capable of passing to opposite sides of obstructions, comprising a main carrier unit, an auxiliary carrier unit, a number of horizontally spaced couplings connecting and supporting said units spaced relative to one another, rollers mounted on at least one of said units for movement of both of said units together over a surface, electrical connections located at each of said couplings and supported in a manner to be disconnected and reconnected upon disconnection and reconnection of said couplings, said electrical connections being wired in parallel, and separate means connected to each of said horizontally spaced couplings which progressively and automatically disconnect and connect each of said couplings and their associated electrical connections upon passing of said units to opposite sides of the obstructions, each of said separate means having a part thereof engageable with and actuated by the obstructions to disconnect its associated coupling and electrical connection to allow passing of the obstruction, and each of said separate means also having another part thereof that reconnects its associated cou-l pling and electrical connection immediately after its coupling and electrical connection have passed the obstruction.

5. A carrier for appliances capable of passing to opposite sides of obstructions, comprising a main carrier unit, an auxiliary carrier unit, a number of horizontally spaced couplings connecting and supporting said units relative to one another, rollers mounted on at least one of said units for movement of both of said units together over a surface, electrical connections located at each of said couplings and supported in a manner to be disconnected and reconnected upon disconnection and reconnection of said couplings, said electrical connections being wired in parallel, arms engageable with and actuated by the obstructions during the passing of said units to opposite sides of the obstructions, each arm being operatively connected to a separate coupling so as to disconnect each coupling and its associated electrical connection during movement thereof past each obstruction, and separate spring means that connect each coupling and its associated electric connection and return its associated arm to its initial position immediately after the passing of said obstructions.

6. A carrier for appliances capable of passing to opposite sides of obstructions; comprising a main carrier unit; an auxiliary carrier unit; a number of horizontally spaced couplings connecting and supporting said units spaced relative to one another for movement of both of said units together over a floor surface; each of said couplings consisting of a spring-urged plunger mounted on one of said units and extendible into the other of said units, locking bolts movable on said spring-urged plunger to positions engageable with the unit into which said plunger is extended so as to attach said units together, and a second spring-urged plunger slidably supported on said first-mentioned plunger for limited movement independent of movement of said first-mentioned plunger, said second-mentioned plunger being connected to said locking bolts and actuating said locking bolts upon the movement thereof relative to said first-mentioned plunger;

and movable arms connected to said second-mentioned spring-urged plungers and engageable With and actuated by the obstructions during the passing of said units to opposite sides of the obstructions so as to slide said second-mentioned plungers, disconnect said locking bolts, and retract said iirst-mentioned plungers upon the engagement of said arms With obstructions, the spring pressures on said plungers providing the source of power to reconnect said couplings and to return their associated arms to their initial positions after the passing of the obstruction.

7. A carrier for appliances capable of passing to opposite sides of obstructions; comprising a main carrier unit; an auxiliary carrier unit; a number of horizontally spaced couplings connecting said units to one another for movement of both of said units together over a floor surface; each of said couplings consisting of a springurged plunger mounted on one of said units and extendible into the other of said units, locking bolts movable on said spring-urged plunger to positions engageable with both of said units so as to attach said units together in spaced relation to one another, and a second spring-urged plunger slidably supported on said lfirst-mentioned plunger for limited movement independent of movement of said first-mentioned plunger,

said second-mentioned plunger being connected to said locking bolts and actuating said locking bolts upon movement thereof relative to said first-mentioned plunger; and movable arms ccnnected to said second-mentioned spring-urged plungers and engageable with and actuated by the obstructions during the passing of said units to opposite sides of the obstructions so as to slide said second-mentioned plungers, disconnect said locking bolts, and retract said iirst-mentioned plungers upon the engagement of said arms with obstructions; the spring pressures on said plungers providing the source of power to reconnect said couplings and to return their associated arms to their initial positions after the passing of the obstruction.

8. A carrier for appliances capable of passing 10 to opposite sides of obstructions; comprising a main carrier unit; an auxiliary carrier unit; a number of horizontally spaced couplings for connecting and supporting said units spaced relative 'to one another for movement of both of said units together over a floor surface; each of said couplings consisting of a spring-urged plunger mounted on one of said units and extendible into the other of said units, locking bolts movable on said spring-urged plunger to positions engageable with the unit into which said plunger is extended so as to attach said units together, a second spring-urged plunger slidably supported on said first-mentioned plunger for limited movement relative to said first-mentioned plunger, said second-mentioned plunger being connected to said locking bolts and actuating said locking bolts upon the movement thereof relative to said rst-mentioned plunger, and electrical connections on one of said slidable plungers and on said unit engaged by said locking bolts adapted to contact with one another; and movable arms connected to said second-mentioned springurged plungers and engageable With and actuated by the obstructions during the passing of said units to opposite sides of the obstructions so as to slide said second-mentioned plungers, disconnect said locking bolts and said electrical connections, and retract said first-mentioned plungers upon the engagement of said arms with obstructions, the spring pressure on said plungers providing the source of power to reconnect said couplings and electrical connections and to return their associated arms to their initial positions after the passing of the obstructions.

VERNON M. JOHNSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,413,575 Cochran Apr. 25, 1922 1,666,954 Wernis Apr. 24, 1928 1,897,362 Daniels Feb. 14, 1933 2,129,165 Conwell Sept. 6, 1938 

